Question: If $x \bigtriangleup y = 6x+y$ and $x \boxdot y = x^{2}+2y^{2}$, find $(-1 \bigtriangleup 5) \boxdot 4$.
First, find $-1 \bigtriangleup 5$ $ -1 \bigtriangleup 5 = (6)(-1)+5$ $ \hphantom{-1 \bigtriangleup 5} = -1$ Now, find $-1 \boxdot 4$ $ -1 \boxdot 4 = (-1)^{2}+2(4^{2})$ $ \hphantom{-1 \boxdot 4} = 33$.